Empirical cover gas correction, sample freezing time, and air buoyancy adjustment for the analysis of uranium in uranium hexafluoride

Technical Report · Wed Jul 31 04:00:00 EDT 1985

OSTI ID:5335408

Hedge, W D

U in UF/sub 6/ can be determined accurately provided the weight of sample is accurately and precisly known. This study provides a basis for setting the time of cooling the sample and the time of cooling the cover gas (nitrogen), the correction for air buoyancy, and the correction for the quantity of cover gas in the container during weighing procedures. The gravimetric analysis of uranium (U) in uranium hexafluoride (UF/sub 6/) necessitates subsampling UF/sub 6/ by transferring an aliquot of liquid UF/sub 6/ through a vacuum manifold to a polytetrafluoroethylene (TFE) sample vial. The aliquot of UF/sub 6/ is frozen into the vial by cooling with liquid nitrogen. Once frozen, a cover gas is admitted to the vacuum manifold and the vial. The vial is then removed in the cover gas atmosphere and sealed with a nut-plug-gasket assembly. The cover gas is admitted to prevent exposure of the frozen UF/sub 6/ to moisture in the atmosphere, and the weight of the cover gas then must be considered as part of the gross weight, but not the net weight of the UF/sub 6/ within the vial. An air buoyancy correction is also applied to correct for the air displacement of the brass weight equivalents used in obtaining the UF/sub 6/ new weight. This empirical study concerns (1) the time required to sufficiently cool the UF/sub 6/ in the sample vial to obtain not only the UF/sub 6/ but also any residual gases present in the sample, (2) the air buoyancy correction required for determining the net weight of UF/sub 6/ contained in the sample vial, and (3) the correction for the quantity of cover gas remaining in the sample vial after sealing. 4 refs., 7 figs., 7 tabs.

• Research Organization: Oak Ridge Gaseous Diffusion Plant, TN (USA)
• DOE Contract Number: AC05-84OT21400
• OSTI ID: 5335408
• Report Number(s): K-2051; ON: DE850183305
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
ACTINIDE COMPOUNDS
ACTINIDES
CHEMICAL ANALYSIS
CORRECTIONS
ELEMENTS
FLUORIDES
FLUORINE COMPOUNDS
GRAVIMETRIC ANALYSIS
HALIDES
HALOGEN COMPOUNDS
METALS
QUANTITATIVE CHEMICAL ANALYSIS
SAMPLING
URANIUM
URANIUM COMPOUNDS
URANIUM FLUORIDES
URANIUM HEXAFLUORIDE
WEIGHT MEASUREMENT